Commutator and method of making same



L. BONSIEUR COMMUTATOR AND METHOD OF MAKING SAME June 7, 1927.

Filed m 1. 1924 VIII/"l/IIA I Q I INVENTOR' B 5;, m 5 ATT'ORNEYS.

' Patented June 7, 1927.

UNITED STATES 1,631,461 PATENT OFFICE.

LE BONSIEUR, OF ELYRIA, OHIO, ASSIGNOR TO THE GENERAL PHONOG-RAIPE MANU-FAG'IURING CO., OF ELYRIA, OHIO, A CORPORATION OF OHIO.-

COm'I'A'IOR AND METHOD OF MAKING- SAME.

Application filed December 1, 1924. I Serial No. 753,411.

My invention relates to commutators and the method of making the same,and relates more particularly to the making of relatively smallcommutators such as are adapted for use upon small electrical motorswhich may be employed in electrical signal horns, for driving phonographmechanisms and for driving toy machinery and the like, although myinvention is not limited to such muses, but may be employed inconnection with the making of commutators for larger motors for drivingfans and for other purposes.

An object of the present invention is to simplify the making ofcommutators for electric motors and the like so that they can be moreinexpensively manufactured in quantities.

Another object of the present invention is to accomplish the making ofsmallsized commutators without the necessity of utilizingany'considerable amount of hand operations incidental to the manufacturethereof.

Another object of my invention is to accomplish the making of smallsized commutator'sof the aforesaid types which will be uniform whenproduced. in large quantities and which will be rugged when completedand which will retain their ability to perform the commutating functionin electric motors even when used for long periods under. severeconditions of use.

Another object of the present invention is to economical y produce inlarge quantities small-sized commutators in which the insulating mediummay be applied as a plastic and which when congealed will efiicientlyhold together the commutator segments and resist deforming of thecommutator by the single or conjoint efi'ects ofheat and mechanicalshocks.

.' Other objects of my'invention and the inventioaitself, will becomeapparent as the description of certain em iments, thereof hereinillustrated and described progresses.

-Refe1ring to the drawings'forming a. part Fig. -1 shows a' side'elevational view of. a

commutator constructed accordingflto the of themethod described herein;6 4

Fig.2 shows the commutator of "Fig. I

viewed from the rear, the view beings. plan view; i 1

the space between the tube 2 and the segprinciplesof my invention byemployment Fig. 3 is a transverse section taken on the line 33 of Fig.1;

Fig. 4 is a longitudinal medial sectional view taken on the line l 1 ofFig. 2;

Fig. 5 shows a plan view of a sheet metal stamping comprising thecommutator segments extending radially from a common center and beingjoined together adjacent such center;

Fig. 6 shows an end view of the joined commutator segments of Fig. 5subsequent to a bending operation in which the radially extendingsegments of Fig. 5 are so bent as to define an approximately cylindricalhollow cup;

Fig. 7 is a side elevation of the formed stamping of Fig. 6:

Fig. 8 is an end plan view of the stamping of Fig. 7 viewing the samefrom below as shown;

Fig. 9 is an end view of the commutator of Fig. 4 seen from below:

Fig. 10 is a longitudinal media] sectional view of a-tool and die forcompressing the congealing plastic insulating material conti' ainedwithin the cup-shaped stamping of In Fi 1 I show a commutator completedand ready to be slipped onto a motor shaft by a tight driving fitthereon preferably, the commutator comprising a centrally disposed tube2 preferably of soft steel and a lurality of commutator segments 3, 4,5, 6,

8 and 9 surrounding the said tube 2 and insulated therefrom byinsulating material 10 which may be of any of a number of differentcompositions, but which I will de-' scribe herein as being of thatmaterial commonly known as bakelite. This bakelite insulating materialextends entirely within ments, and also extends between the seg mentsnear one end thereof and around the segments as shown at 11. The portion11 of the insulating material joined to the inner portion 10 thereofforms a band or ring of insulating material outside the com-- mutatorsegments and adjacent the termi-" nals 12 of the segments, and preventsany ,portion of the solder or sol eri g fluxes employed in soldei'lnelectricalconductors to the terminals 12 om flowing out over the contentportions 13 of the se ents.

The insulating material also protru es bemechanical blows, shocks andvibrations.

The steel tube 2 is preferably contained within the body of insulatingmaterial 10 particularly where the commutator is to be made in thelarger sizes-as it may be driven onto a motor shaft very tightly andwithout the danger of thereby causing the body of the commutator to beexpanded unduly and beyond its elastic limit to crack the commutator,The commutator, .however, may be used with or without the tube 2, itsuse being optional and desirable principally in the larger sizes ofcommutators. J L

The commutator of Figs. 1 to 4 inclusive is preferably formed from asingle sheet metal stamping such as a stamping of brass or copper, ingcut in a form such as that shown in Fig. 5 wherein the commutatorsegments 3 to 9 inclusive are shown as extending radially from a commoncenter whereat the stamping is referably perforated as shown at 15 and te segments being joined together b a connecting ring of the stampingmaterial shown at 16. The perforations 17 may be provided, their usebeing optional, but where provided as-shown the b ank may be more easilybent adjacent such perforations, and the material may be cut away atsuch perforations somewhat more easily.

The en 3 of the segment portions are referabl formed in the acceptedshape or electrical terminals as shownat 12 comprising a,hook portion 18adapted to receive an electrical. circuit conductin wire which may besoldered to the termmal 12 after the commutator 'has been completed andplaced on a motor shaft. The stamping as shown in Fig. 5 is'thenplacedin a punchpress and in the manner usual for such pressm o rations,the radially extending arms o t stamping comprising the segments 1n theultimate product are bent into substantially cylindrical form as shownin the figure, and the ring shaped joining porher: 16 forming the bottomwall of the cupshaped article so formed. The resultant integrally formedpiece is illustrated inFi 6 to 8 lnclusive which show respectively t eartlcletein (21ndi plan, sideh elpgational dand opposi en an views e'acent e of the so-cali I ges elusive may be machined at this stage ofthe operation by running a cutting saw be tween the segment arms. Thismachining operation, however, may be omitted as the a acent edgesgenerally are suficiently ed segment arms 3 to 9 1nregular and spacedthat no machining is necessary. v I I The cup-shaped article is thenlaced in a die recess and filled with ba elite insulating material inpreferably powdered recessed from the surface 23 of t e die and having astepped portion 24 at the bottom of the cavity, the recess 24 andshelf22 as well as the interior 25 of the cavity being filled with heatedbakelite which While being congealed from plastic condition is subjectto the pressure of a pressure tool 19 pressed downwardly over the ends12 of the commutator segments and into intimate pressure creatingcontact with the body of lnsulating material congealing within thecavity.

The tool so-called segments in an annular shaped recess on the bottomface of the tool, the depth of the recess being suflicient to clear theends of the terminals 12.

19 receives the ends 12 of the,

After the commutator is thusformed it ring 16 whereby the segments 3 to9 inclusive will be separated and electrically insulated one from theother as shown in Figs. 1 and 4. The finished commutator is shown 1n Fires 1 and 4, and as therein shown comprises a pluralit 3 to 9 inclusive,iaving contact surfaces 52,

of commutator segments' each forming a portion of the completecylindrical outer surface of the commutator the insulating material 25connecting all of the segments and holding them against dislodgement,filling the inner se s aces and preventing the spacing t e segmentsbecoming'modified.

The axial bore of t e commutator is made tween of such a size that t 'ecommutator will fit tightly on the end of a motor shaft makingfrictional contact therewith and this frictional contact may beincreased by knurling or otherwise roughening the motor shaft at thepoint where the commutator is forced onto it. I prefer, however, tosolder the entab' 120.

I electrical circuit conductors leading the motor armature windings tothe terminals 12 of the commutator segments.

Having thus described my invention in different embodiments, I am awarethat the same may be practiced according to the principles of myinvention, but according to methods departing colorably from thecomplete method herein described for accomplishing the result of myinvention and that the product of the method herein described may beproduced by other methods, but such departures will be comprehended inthe spirit of my invention and in the accompanying claims.

I claim 1. The method of'making ,a commutator comprising a plurality ofsegments, consist-, ing of cutting from sheet metal a piece havingradially extending arms joined at their inner ends, then bending thearms so as to approximately define a cylindrical cup, then in placing aplastic congealablc insulating compound within the substantiallycup-shaped article thereby produced and permitting a portion of thecompound to flow between the arms to form a band surrounding the armsbut united thereto, and to the rest of the compound Within the arms,permitting the compound to congeal and subsequently removing the portionof .the sheet metal joining the inner ends of the arms.

2. A commutator having a plurality of segments, each of said segmentscomprising an intermediate portion having an outer contact surface, thecontact-surfaces ofthe segments being so formed as to approximatelydefine a cylinder, an end of each segment being turned inwardly, and abody portion of cementitious congealable insulating material uniting andspacing the segments, said body portion having a bore axial to thesegment contact surfaces, and an insulating band surrounding thesegments at a point adjoining their contact surfaces, said band beingunited firmly to the said insulating material body portion by connectinginsulating material portions extending between the segments.

3. A commutator having a plurality of segments, each of said segmentscomprising on intermediate portion havin an outer contact surface, thecontact surfaces of the segments being so formed as to approximatelydefine a cylinder, an end of each segment being turned inwardly, and abody portion of cementitious congealable insulating material uniting andspacing the segments, said body portion having a bore axial to thesegment contact surfaces, and an insulating band surrounding thesegments at a point adjoining their contact surfaces.

In testimony whereof I hereunto affix my signature this 25th day ofNovember, 1924.

LE BONSIEUR.

